Method for determining measured data from the stomach of a patient

ABSTRACT

In a method to obtain measurement data from the stomach of a patient using an endoscope, a degassed aqueous drink solution is administered to the stomach of the patient and the measurement data are acquired with the degassed aqueous drink solution present in the stomach.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a method to determine measurement data from thestomach of a patient, of the type wherein an endoscope is used toacquire measurement data in the stomach of a patient and an aqueousdrink solution is present in the stomach of the patient. The inventionmoreover concerns a drink solution for the implementation of such amethod.

2. Description of the Prior Art

As used herein, an endoscope means both a generally known, classicalendoscope which is brought into the stomach of a patient with the use ofa tube directed through the mouth or nose of the patient, and a capsuleendoscope (known for example from DE 101 42 253 C1) that the patient canindependently swallow. A drink solution is a liquid provided for use inthe field of medicine that is selectively brought into the stomach of apatient with a stomach probe or is administered to the patient forindependent ingestion.

An endoscopically implemented examination of the human or animalstomach—a gastroscopy—is part of a routine examination in everydaymedical practice. Within the framework of the gastroscopy, differentvariables, measurement values or samples are taken inside the stomachand provided to a physician or assistant for evaluation. For example,content substances or concentrations of the stomach contents aremeasured, the chemical composition of the gastric juices are determinedor image data of the stomach mucosa are collected.

In classical endoscopy, a tube is directed through the mouth or nose ofthe patient into his stomach. Since the stomach is a hollow muscle, thisis normally expanded by blowing in a gas (for example air or CO₂), inparticular for the implementation of visual examinations. As a result ofthis expansion, regions of the stomach that are otherwise covered by themucosa folds are also accessible.

A variant that is more comfortable and gentle for the patient relativeto classical gastroscopy uses a capsule endoscope that can be swallowed.To transfer measurement data from inside the stomach, the capsuleendoscope/the endoscopy capsule is connected (for example via a radioconnection) with a transmission station placed in proximity to thepatient. For targeted acquisition of measurement and/or image data fromspecific regions of the stomach, the capsule endoscope can bemagnetically navigable. This type of capsule endoscopy is alsodesignated as MGCE (Engl.: magnetically guided capsule endoscopy). Forexample, a capsule endoscope that is suitable for this method arisesfrom DE 101 42 253 C1, which was already mentioned. In contrast toconventional gastroscopy, in capsule endoscopy the stomach is expandednot with a gas but rather with the aid of a liquid. However, multiplemeasurement errors have been observed in the acquisition of measurementdata.

SUMMARY OF THE INVENTION

An object of the invention is to provide a method to determinemeasurement data from inside the stomach which is improved with regardto its precision. The invention also encompasses a drink solution forapplication in such a method that allows an improved accuracy in themeasurement value acquisition.

In the method according to the invention an endoscope to acquire themeasurement data is present in the stomach of the patient to obtainmeasurement data from said stomach.

During the acquisition of the measurement data, an aqueous drinksolution that is previously degassed is present in the stomach of thepatient.

As used herein, a degassed drink solution is a drink solution that isfree of dissolved gases at least insofar as that gas bubble formation isnearly precluded when this is brought into the stomach of the patient.The conditions prevailing in the stomach of a patient are to be takeninto account in this context. The drink solution is thus degassed atleast insofar as that this no longer outgasses given the conditionsprevailing in the stomach of the patient, for example with regard totemperature, pH value etc. A complete degassing of the drink solution isnormally not necessary in this context.

The method according to the invention is based on the following insight.

The expansion of the stomach with the use of a liquid that isparticularly advantageous for capsule endoscopy entails differenttechnical problems. However, the following statements apply for bothclassical endoscopy and capsule endoscopy.

For example, reactions can occur between the liquid used for theexpansion and the stomach contents, in particular the gastric juices.The formation of gas bubbles has been observed multiple times in thechemical and/or physical interaction between the liquid and the stomachcontents. A gas bubble development inside the stomach has been connectedwith the occurring measurement errors of the probes present in theendoscope.

A bubble development is particularly critical for the acquisition ofoptical image data of the stomach mucosa. Finely distributed bubblesdissolved in the liquid used to expand the stomach reduce its opticalquality and lead to a high proportion of scattered light in the imagedata. Moreover, bubbles adhering to the outside of the capsule can causeimage errors since the optics used to acquire the image data areentirely or partially covered.

The gas bubble formation inside the stomach is particularly problematicfor a magnetically navigable capsule endoscope. For example, an adhesionof gas bubbles to the surface of the capsule leads to unwanted localbuoyancy forces that can cause the capsule to tumble but at leastsignificantly hinder its navigability.

In summary, the bubble formation occurring in the stomach could beidentified as a primary cause for arising measurement errors. To avoidthe gas formation, the drink solution is degassed according to theinvention. This measure is motivated by the following considerations.

The drink solution that is transported into the stomach to expand it isin contact with both the stomach contents and the stomach mucosa. Afterthe drink solution has been introduced into the stomach of the patient,various chemical reactions can occur between this and the stomachcontents or, respectively, the gastric juices produced by the stomachmucosa. One example is the variation of the pH value of the drinksolution due to the (typically acidic) gastric juices. If the pH valuedrops, the solubility of CO₂ in water decreases, such that thisoutgasses. This and other reactions have been connected with a gasformation inside the stomach. An additional effect that leads to the gasbubble formation inside the stomach is the warming of the drinksolution. In that the temperature of the drink solution increases—forexample from room temperature or below this to the typical temperatureof the stomach—the solubility of the gases present in the drink solutiondecreases, whereby these escape. In order to suppress the gas bubbleformation that has been repeatedly observed, the drink solution isdegassed before this is brought into the stomach of the patient. Thedrink solution is thus freed of dissolved gases at least insofar as thata gas bubble development is nearly precluded if said solution is broughtinto the stomach of the patient. Particular attention is thereby grantedto the gases CO₂, N₂ and O₂. These gases represent the primarycomponents of ambient air and are correspondingly dissolved in drinkingwater, for example. The drink solution is advantageously predominantlyfreed of these gases.

The gas bubble development that is suppressed in this manner has anadvantageous effect on the precision of the measurement values detectedwith the endoscope. In conventional measurement methods that use a drinksolution that has not been degassed, it has been repeatedly observedthat gas bubbles adhere to the sensors of the endoscope and in this waycause severe measurement errors. In particular in the acquisition ofoptical image data, severe distortions occur in conventional measurementmethods. For example, the drink solution can become turbid due todissolved gas bubbles, such that the image data appear indistinct orexhibit a high proportion of scattered light.

Both the determination of image data from inside the stomach of thepatient and the determination of additional measurement data becomessignificantly more reliable due to the degassing of the drink solution.

The aqueous drink solution according to the invention that is for use ina measurement method in which this is present in the stomach of apatient in additional to an endoscope for acquisition of measurementdata is characterized in that this solution is degassed. As has alreadybeen mentioned above, the drink solution is freed of dissolved gases atleast insofar as that a gas bubble development is nearly precluded whenthis is brought into the stomach of the patient.

Significant advantages of the drink solution according to the inventionhave already been cited in connection with the method according to theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following the invention is explained further using variousexemplary embodiments.

To prepare the measurement a degassed drink solution is administered tothe patient. The drink solution can be independently taken by thepatient, but it can also be brought into his stomach with a probe, forexample. The fluid level in the stomach of the patient can be monitoredwith the aid of ultrasound. In order to compensate for an outflow of thedrink solution from the stomach, during the implementation of themeasurements drink solution can moreover be additionally drunk by thepatient or be brought into his stomach in another manner.

Within the scope of the preparation of the drink solution, according toa first exemplary embodiment this is subjected to a vacuum degassingbefore it is brought into the stomach of the patient. The vacuumdegasing is easily controllable via technical measures and isinexpensive; it can possibly be supported via additional measures fordegassing. For example, the drink solution can additionally be heated toexpel the dissolved gases.

Osmotic reactions at the stomach wall represent an additional source forthe gas bubble formation inside the stomach. According to a furtherexemplary embodiment, these reactions can be suppressed via an isotonicpreparation of the drink solution. The drink solution that ispre-treated in such a manner has the same osmotic pressure as humanblood. Osmotic reactions at the stomach mucosa can thus be avoided. Thegas bubble development inside the stomach can be prevented or at leastcan be severely reduced via the reduction or significant avoidance ofsuch osmotic reactions at the stomach wall. The drink solution ispreferably prepared isotonically via the addition of sodium chloride,i.e. is compounded with 0.9% by weight of cooking salt.

Among other things, an additional problem in the acquisition ofmeasurement data inside the human or animal stomach is foaming caused bythe peristalsis of the stomach. Foam that is present in the stomach inparticular hinders the acquisition of optical image data. This appliesfor both a conventional endoscope and for an endoscopy capsule. In thefollowing reference is made to a capsule endoscope as an example.

The endoscope possesses one or more cameras to acquire image data. Inits working position the endoscopy capsule is located at or in proximityto the surface of the drink solution located in the stomach. Theendoscopy capsule advantageously possesses multiple cameras, of which afirst camera acquires optical data of the stomach mucosa through thedrink solution from below the liquid level, for example. An additionalcamera can be arranged above the liquid level to acquire image data. Inparticular, the latter is significantly affected by foam formationinside the stomach.

Foam present in the stomach hinders the acquisition of optical imagedata; however, other sensor that are possibly present at the endoscopecan be disrupted by foam present in the stomach. To improve the workingconditions of the endoscope inside the stomach, the drink solution iscompounded with a defoaming agent, advantageously with a silicone oil.The use of silicone oil is particularly advantageous since this isphysiologically harmless; silicone oil is inert inside the body, as isknown from silicone implants. The addition of silicon oil produces areduction of the surface tension of the drink solution provided in thestomach. This leads to a reduction of the foam formation.

As already mentioned, in addition to optical image data the endoscopecan also detect additional variables, for example concentrations ofspecific content substances present in the stomach. One example is themeasurement of the ammonia content of the stomach contents. Ammoniaexists as both NH₃ and NH₄ ⁺ in an aqueous environment. The equilibriumbetween NH₃ and NH₄ ⁺ shifts depending on the pH value prevailing in thestomach. To determine a significant measurement value of the NH₃concentration it is decisive that the pH value in the stomach of thepatient has approximately the same value in every measurement. This inparticular applies for a time-dependent measurement of the NH₃concentration. In such a measurement the variation of the NH₃concentration in a certain time period is observed. Such a measurementcould be disrupted by the continuously occurring production of gastricjuices, for example. For this reason, according to a further exemplaryembodiment the drink solution is compounded with a pH buffer. A citricacid-phosphate buffer is advantageously used. Such a buffer (also calleda Mcllvaine buffer) can be adjusted in a pH range between 2.2 and 8. Itsbuffer range thus lies in a range of the acid environment of thestomach. A mixture of 0.1 molar citric acid (solution A) and 0.2 molarNaHPO₄.4H₂0 solution (solution B) of buffer composition X ml A+(100−X)ml B is designated as a McIlvaine buffer.

By adding a pH buffer, constant conditions can be set in the stomach ofthe patient. This is also advantageous for the acquisition of opticalimage data since variations in the index of refraction of the drinksolution that are caused by variations of the pH value can be avoided.

As already stated, optimally constant conditions inside the stomach areto be sought for the acquisition of measurement data. This requirementextends not only to the chemical composition of the stomach contents butalso to the amount of liquid present in the stomach, for example. Ingeneral, a drink solution provided into the stomach remains there onlyfor a relatively short period of time. According to a further exemplaryembodiment, the temperature of the drink solution is calibratedessentially to the temperature of the stomach to extend the residenceduration. A drink solution that is preheated to approximately bodytemperature has multiple advantages. On the one hand,temperature-dependent density changes within the drink solution do notoccur. Such density changes lead to variations in the index ofrefraction of the drink solution and thus lead to streak formation inthe image data. Moreover, a warm drink solution will drain more slowlyfrom the pylorus into the duodenum than a cold drink solution. Theresidence duration of the preheated drink solution in the stomach isthus improved.

In addition to classical endoscopy and capsule endoscopy, thepossibility moreover exists to use a magnetically navigable capsuleendoscope to detect measurement values in the stomach of a patient. Theaforementioned measures that largely suppress a bubble formation withinthe stomach of a patient are in particular relevant when such amagnetically controlled endoscopy capsule is used.

A technical problem which occurs in the use of a drink solution that hasnot been degassed is that bubbles accumulate on the outside of theendoscopy capsule. The bubbles—which have accumulated in a partialregion, for example—lead there to local buoyancy forces at the capsuleendoscope, whereby its control is made significantly more difficult. Inthe worst case, the capsule can start to tumble; in this case a targetedmeasurement value acquisition is impossible.

The use of a degassed drink solution prevents the situation that bubblescan accumulate at the surface of the capsule endoscope. The capsuleendoscope can be navigated without problems. The navigability/mobilityof the endoscope capsule inside the stomach can be additionally improvedin that a silicone oil is admixed with the drink solution. In additionto the aforementioned effect that the bubble formation is reduced, thishas the effect of a lubricant. The friction forces between the capsuleendoscope and the drink fluid and between the capsule endoscope and thestomach wall are reduced; the navigability of the capsule is improved.

In order to enable a friction-less workflow of the measurements in thestomach of the patient, the drink solution can be provided with theadmixtures and be degassed insofar as this is necessary. Such a prepareddrink solution must merely be correspondingly tempered before it isbrought into the stomach of the patient. Such a prepared drink solutionallows a high workflow in the measurement value acquisition.

With the use of the described measures it can be achieved that thephysical and chemical properties of the drink solution achieve optimallyconstant conditions in the stomach of the patient during the measurementvalue acquisition. The measurement value acquisition is more reliableand reproducible.

Although modifications and changes may be suggested by those skilled inthe art, it is the intention of the inventors to embody within thepatent warranted heron all changes and modifications as reasonably andproperly come within the scope of their contribution to the art.

1.-17. (canceled)
 18. A method for acquiring measurement data from thestomach of a patient, comprising the steps of: degassing an aqueousdrink solution and thereafter administering the degassed aqueous drinksolution to the stomach of a patient; and acquiring measurement datafrom the stomach of the patient using an endoscope with said degassedaqueous drink solution present in the stomach of the patient during theacquisition of the measurement data.
 19. A method as claimed in claim 18comprising degassing said aqueous drink solution by vacuum degassing.20. A method as claimed in claim 18 comprising preparing said aqueousdrink solution isotonically.
 21. A method as claimed in claim 20comprising preparing said aqueous drink solution isotonically by addingNaCl thereto.
 22. A method as claimed in claim 18 comprising compoundingsaid aqueous drink solution with a silicone oil.
 23. A method as claimedin claim 18 comprising acquiring image data as said measurement datausing a camera contained in said endoscope.
 24. A method as claimed inclaim 18 comprising compounding said aqueous drink solution with a pHbuffer.
 25. A method as claimed in claim 24 comprising employing acitric acid phosphate buffer as said pH buffer.
 26. A method as claimedin claim 18 comprising calibrating a temperature of the degassed aqueousdrink solution to a temperature of the stomach.
 27. A method as claimedin claim 18 comprising acquiring said measurement data with amagnetically controllable capsule endoscope.
 28. An aqueous drinksolution comprising a basic aqueous drink solution formulated to beadministered into the stomach of a patient, said basic aqueous drinksolution being degassed so as to be substantially free of dissolved gastherein.
 29. A drink solution as claimed in claim 28 wherein said basicaqueous drink solution is isotonic.
 30. A drink solution as claimed inclaim 29 containing NaCl in isotonic concentration.
 31. A drink solutionas claimed in claim 28 containing silicone oil.
 32. A drink solution asclaimed in claim 28 compounded with a pH buffer.
 33. A drink solution asclaimed in claim 32 comprising a citric acid phosphate buffer as said pHbuffer.